Answer:
Two human needs are food and water. We need food to survive so we dont starve to death. And water is most important because without water after around five days, you die. Heat technology could be fire. We use fire to distill salt water. Distilling salt water boils the bacteria and so it would be safe to drink. We also use fire to cook the food we have gotten or hunted so we dont get infected with deadly bacteria and viruses.
Explanation:
Hope this helps. Have a nice day!
The answer is A because when an atom has more electrons in its outer shell, It becomes more reactive
Answer:
Your answer is B. Energy cannot be destroyed
Explanation:
The total amount of energy remains constant in an isolated system. It states that energy can neither be created nor destroyed, but it can change from one form to another.
Answer:
Here's what I get
Explanation:
You want to dilute the original solution by a factor of 25 in two steps, so you could dilute it by a factor of 5 in the first step, then dilute the new solution by another factor of 5.
A. First dilution
Use a 10 mL pipet to transfer 10 mL of the original solution to a 50 mL volumetric flask. Make up to the mark with distilled water. Shake well to mix.
Use the dilution formula to calculate the new concentration.
B. Second dilution
Repeat Step 1, using the 0.003 970 mol·L⁻¹ solution.
3. Check:
Compare the final concentration with the original
The solvent is <span>ch3ch2ch2oh with a volume of 387 mL which is equivalent to
387 mL (0.811 g/mL) (1 kg /1000 kg) = 0.3139 kg
The moles of the alchol is
25.5 mL (0.792 g/mL) (1 mol/32 g) = 0.631 mol
The molality is
0.631 mol / 0.3139 kg = 2.01 mol/kg</span>
